Do chewing gums and sweets containing xylitol prevent caries in children?

Three electronic databases (Pubmed, Embase and the Cochrane Library) were searched in December 2022, and again for additional literature on 3–5th January 2023. Reference lists of relevant systematic reviews were hand searched for other eligible studies for inclusion. Randomised controlled clinical trials and controlled clinical trials conducted on children (aged ≤ 18 years), conducted between 1974–2022 and available in English, were eligible for inclusion. Studies were excluded if caries was not an outcome, the control group was not sufficient, they were lab-based studies or studies where xylitol delivery was not a sweet or chewing gum and where the xylitol product contained a component such as fluoride which may influence the outcomes. Four calibrated reviewers independently screened titles and abstracts, and disagreements were resolved via group discussion. Preventative effect was determined by comparing the mean caries increment in the control and intervention groups, producing a preventative fraction. A total of 617 titles were initially screened for relevance. After duplicate removal, 268 abstracts were screened and 16 full text articles reviewed, with one more study then excluded. 10 studies investigated xylitol-containing chewing gum, and six looked at xylitol candy (one did both). Eight included studies were randomised controlled trials. Data extraction was undertaken by two reviewers. 3466 participants were included in the 10 studies that investigated xylitol chewing gum, and all 10 studies reported a statistically significant preventive effect compared to a no chewing gum or placebo control. In 9 studies, the preventive fraction was clinically significant. The six studies investigating xylitol candies contained a total of 1023 participants, and only one study demonstrated a significant preventative effect. There is some evidence that incorporating xylitol chewing gum daily has a caries-reducing effect in those with a moderate-to-high baseline caries level. This effect was not present for xylitol sweets.